Furnace



Jan. 1, 1935.

R. M. HARDGROVE FURNAC E Filed Aug. 13, 1930 3 Sheets-Sheet l lllllll llll II INVENTO flaw 7M5 BY I/CLLU I ATTORNEY} Jan. 1, 1935, R. M. HARDGROVE 4 1,986,664

FURNACE Filed Au 13, 1930 a Sheets-Sheet 2 16 J1 1 7 a F-|G.2.'

Jan. 1 1935. R HARDGRQVE I 1,986.664

. FURNACE Filed'Aug. 15, 1930 s sne'bxs sneet z 37 1 .fZ' VFIQA' FIGS.

I ATTORNEY Patented Jan. l, 1935 UNITED STATES PATENT OFFICE FURNACE Ralph M. Hardgrove, Bethlehem, Pa., assignor to Fuller Lehigh Company, Fullerton, Pa., a corporation of Delaware Application August 13, 1930, Serial No. 475,009

12 Claims. (Cl. 122-235) This invention relates to furnaces that are proof the furnace 1. These tubes are lined with vided with openings through the walls of the tile or Bailey blocks 12, as indicated. The lower furnace for withdrawing molten slag that colends of the tubes 11 are bent outwardly and exlects upon the floor of the furnace from hot prodtend into the horizontal headers 13.

nets of combustion in the furnace. This inven- Tubes 14 extend from the water space of the 5 tion is especially useful in connection with fursteam and Water drum to the headers 13 and naces in which powdered fuel is burned and the tubes also extend to the headers 13 from the floor of the furnace isinclined so that the molten headers 15' to which the downtake tubes 8 are slag will collect in such a way that its greatest connected.

l0 depth is near the slag tapping opening and de- It will be observed that the tubes 11 and blocks 10 creases to a thin section or feather edge along 12 forming the inclined walls of the hoper-shaped one or moreedges of the slag. lower portion are continuations of the side walls Hitherto in furnaces that are provided with of the furnace. It is to be observed, however, slag tapping openings for withdrawing molten that my invention in certain of its broader as- 15 slag, the layer of slag is sometimes permitted to pects is not limited to side walls having inclined 15 cool in the furnace with its edges in contact with lower portions, for other constructions may be the walls of the furnace so that subsequent exresorted to without departing from the intended pansion due to heating the slag again displaces scope of my invention, for example, aconstruction the walls of the furnace. By the present invenmay be used like that shown in my copending tion the water cooled floor of the furnace is inapplication, Serial #475,010, filed August 13, 1930, 20 clined so that one or more edges of the slag bewherein the side water walls extend vertically comes sufficiently thin in order that it may fail from the top to the bottom of the combustion under compression due to expansion before exchamber. cessive strain is exerted upon the furnace walls. A row of inclined floor tubes 16 that may be The invention will be understood from the destraight and parallel to each other, passes across 25 scription in connection with the drawings, in the space between the'inclined hopper walls,these which Fig. 1 is a vertical section through a boiler tubes passing between the tubes 11 in the hopper illustrating the invention; Fig. 2 is a section along walls. The ends of the row of tubes 16 are conthe line 2-2 of Fig. 3; Fig. 3 is a section, along nected'to parallel inclined headers 17 and 18, a

the line 3-3 of Fig. 1; Fig. 4 is a section similar header 1'7 being at a higher elevation than the 30 to Fig. 2 taken along the line 4-4 of Fig. 5, showheader 18. A tube 19 extends from the water ing a modification; and Fig. 5 is a vertical secspace'of the steam and water drum 10 to the lower tion through the floor of a furnace showing the end of the header l8, and a tube 20 extends from modification. the upper end of the header 1'? to the steam space In the drawings, reference character 1 indiof the steam and water drum 10. Tile 21 are 35 cates a. furnace located below a boiler and pro- Placed upon the inclined tubes 16 to provide a vided .with one or more fuel burners 2 through continuous floor for the furnace. the front wall of the furnace. Water circulates from the water space of the Vertically disposed water tubes 3 are provided Steam and Water drum 10 through the tubes in the front and rear walls of the furnace and h r 3, h pper wall tubes 11, headers 6, fur- 4o vertically disposed water tubes4 are provided in na W ll t b s 3 a d header '7 andtubes 9 to th sid w ll of the furnace, Th tub 3 d 4 the steam space of the steam and water drum 10. are lined with tile or the well-known Bailey blocks Recirculating Water 9180 9 68 from he eaders 5. The lower endsof the tubes 3 and 4 are conthrough tubes headers 5 and tubes 15 back nected to lower horizontally disposed headers 6 t0 the headers 13. Water also circulates from the 45 and the upper ends of these tubes extend o twater space of the steam and water drum 10 wardly and are connected to upper horizontally through the tube 19 to the header l8, thence disposed headers '7. Downtake pipes 8 are conthrough the floor tubes 16, header 1'! and tube 20 nected to the upper headers 7 and uptake pipes to the steam space of the steam and water drum.

9 connect the headers 7 to the steam space of the The floor of the furnace is rectangularly shaped 50 steam and water drum 10 of the water tube boiler with one corner lower than the others and a slag that is located above the furnace 1. tapping hole 22 is provided through the wall of the Rows. of inwardly inclined tubes 11 extend furnace near the lowest corner of the floor. -The downwardly from the headers 6 and form the molten slag from the hot products of combustion inclined walls of the hopper-shaped lower portion collects on the floor with its greatest depth at the 55 lower corner while the edge away from this corner thins out in a wedge shape so that after it solidifies and is subsequently heated, the expansion thereof will not exert enough horizontal thrust to cause the furnace walls to be displaced. Also the meeting of the edges of the floor with the sloping sides of the hopper-shaped bottom at an obtuse angle aids in eliminating the danger of the slag forcing the furnace walls outwardly as the edges of the slag have a tendency to move upwardly along the sloping surface of the hopper when expansion takes place.

It will be evident that the slag tapping hole 22 provides means for tapping and draining the pool of molten slag through one of the furnace walls from below the surface of the pool. Appropriate means such as an ordinary plug may be provided for closing the slag tap opening 22 so that the pool of slag may be allowed to accumulate.

In the modification shown in Figs. 4 and 5, the row of straight parallel water tubes 26 along the flo'or of the furnace have their upper ends connected to the upper header 2'7 which slopes downwardly from its middle to each end, and their lower ends are connected to the corresponding lower header 28. Tile 29 are placed upon the tubes 26 to formthe continuous floor of the fur- .nace. By this arrangement the floor of the furnace is made to slope in two directions.

- line 30 so that when the slag collects on the floor it will assume the positions indicated by the reference character 23 with the edges of the slag away from the lowest corners thinned out along the fioor.

It has been found that with water cooled floors of this type, the molten slag freezing in cracks or crevices that may be left in the floor prevents the remaining slag from leaking through and that slag-tight joints can be maintained between the edges of the floor and the walls of the furnace. When in former installations of this character a layer of slag is permitted to solidify, cracks may form in it which later become filled up with molten slag which may bepermitted to freeze later, so that the slab of slag gradually grows during successive periods of cooling and exerts a very strong pressure against the walls of the fur- This objection is overcome by the present invention. The thin edges of the slag will be crushed without displacing thewalls of the furnace.

I claim:

1. In a furnace, a fioor constructed to sustain a pool of molten slag, upwardly extending walls adjacent said floor, said fioor sloping downward to one corner of the furnace floor between adjacent upwardly extending walls.

2. In'a furnace, a hopper-shaped lower portion, water tubes in said hopper-shaped lower portion for cooling the same, a floor constructed to sustain a pool of molten slag extending across said hopper-shaped lower portion, said floor sloping to one corner of the furnace floor, water tubes in said fioor for cooling the same, and means forming a slag tap opening at the lower corner of said floor, substantially as described.

3. In a furnace for burning slag forming fuel, upwardly extending side walls comprising spaced water tubes and closure elements for the spaces, a horizontally inclined furnacefloor constructed to sustain a pool of molten slag and comprising at least a single row of transversely spaced water tube lengths each extending from wall to wall of said furnace, and closure elements for the spaces between said tube lengths and disposed to completely seal the said tube space, and means forming a slag tap opening in tube space of the upwardly extending side wall at the lower end of said floor and adjacent a second upwardly extending wall.

4. In a furnace for burning slag forming fuel, opposed upwardly extending side walls comprising spaced water tubes and closure elements for the spaces, a horizontally inclined furnace floor constructed to sustain a pool of molten slag and comprising at least a single row of transversely spaced water tube lengths each extending from vwall to wall of said furnace, and closure elements for the spaces between said tube lengths and disposed to completely seal the said tube space, and means forming a slag tap opening in one of said side wall tube spaces adjacent a location of lowest floor elevation.

5. In a furnace for burning slag forming fuel, upwardly extending side walls comprising spaced water tubes and closure elements for the spaces, said walls defining a furnace of rectangular section, a horizontally inclined furnace floor constructed to sustain a pool of molten slag and comprising at least a single row of transversely spaced water tube lengths, each extending from wall to wall of said furnace and closure elements for the spaces between said tube lengths, said floor sloping downwardly to a corner thereof between adjacent upwardly extending walls.

6. In a furnace for burning a slag forming fuel, upwardly extending side walls comprising spaced water tubes and closure elements for the spaces, and a furnace bottom comprising a central horizontally extending portion, and margin portions inclined to said central portion, said horizontally extending portion and said margin portion each having a row of spaced Water tubes and space closure means.

7. In a furnace, a floor constructed to sustain a pool of molten slag, upwardly extending walls circumscribing said floor, said floor sloping downward to one corner of the furnace at the juncture of adjacent upwardly extending walls, and means forming a slag tap opening adjacent the corner of the furnace floor toward which said floor slopes.

8. In a furnace, a floor constructed to sustain a pool of molten slag, upwardly extending walls circumscribing said floor, said floor sloping downward to one corner of the furnace at the juncture of adjacent upwardly extending walls, water tubes in said floor for cooling the same, and means forming a slag tap opening adjacent the corner of the furnace floor toward which said floor slopes.

9. In a furnace for burning slag forming fuel, the combination of upwardly extending water cooled walls defining a combustion chamber;

each wall comprising a row of spaced water cirthe bottom comprising at least a single row of transversely spaced water tube lengths extending from one wall of the furnace to an opposite wall, an inlet header connected to one end of the row of tube lengths and an outlet header connected to the opposite end of the row of tube lengths, and closure means for the spaces between tube lengths and constructed to completely seal the spaces between tubes throughout their lengths so as to prevent leakage of slag therethrough.

10. In a furnace for burning a slag forming fuel, water cooled front, rear and side walls, a furnace bottom constructed to sustain a pool of molten slag extending over at least a substantial part thereof and comprising a row of transversely spaced horizontally inclined water tube lengths extending from wall to wall of said furnace, closure means for the spaces between said lengths and disposed to completely seal the said tube spaces throughout their lengths, and a burner for projecting fuel for combustion through the wall at the upper ends of the inclined tubes and directing such fuel toward the point of greatest depth of the slag pool.

11. In a furnace for burning a slag formin fuel, water cooled front, rear and side walls, a water cooled bottom constructed to sustain a pool of molten slag over at least a substantial part thereof and of greater depth at one point than another, a burner projecting fuel for combustion into the furnace through said front wall and downward and toward the rear wall, said point of greatest depth being nearer the rear wall than the front wall;-

12. In a furnace for burning a slag forming fuel, water cooled front, rear and side walls, a furnace bottom constructed to sustain a pool of molten slag over at least a substantial part thereof and comprising at least a single row of transversely spaced horizontally inclined water tube lengths extending from wall to wall of said furnace, closure means forthe spaces between said lengths and disposed to completely seal the said tube spaces throughout their lengths, a burner tubes and toward the opposite portion of the furnace, and a slag tap opening at points remote from said last mentioned wall.

RALPH M. HARDGROVE. 

